Abstract: The present disclosure provides a positron emission tomography (PET)-detectable 1-((2-fluoro-6-[18F]fluorophenyl)sulfonyl)-4-((4-methoxyphenyl)sulfonyl)piperazine ([18F]DASA-23) probe that can selectively bind to the pyruvate kinase variant M2 (PKM2) found in cancer cells, such as of human glioma. Given the importance of PKM2 in the regulation of tumor metabolism, there is an on-going need to non-invasively measure its expression through the development of PKM2-specific radiopharmaceuticals. Precursors useful for the synthesis of the radiolabeled [18F]DASA-23-PKM2-specific probe and related compounds, and their methods of synthesis, are provided. Since the half-life of the 18F isotope is approximately 110 min, it is advantageous for a practitioner to attach the radionuclide to the precursor shortly before administration. Therefore, a precursor compound suitable for receiving the radionuclide and capable of specifically binding to the PKM2 variant can be provided.